From PLANT West: SAPing bitumen

Butane taps freer flowing oil.

Cenovus uses a solvent enhancement to improve SAGD production efficiency and reduce its carbon footprint.

To most people, butane is something that fuels cigarette lighters, but it does have other uses. Soon it will be used in an innovative process that will boost bitumen recovery rates from Alberta’s oil sands.

Innovation is more critical than ever as energy producers work to reduce their carbon footprints, while improving efficiency as the need for oil sands production continues to grow. Indeed, global demand for energy is expected to increase 47% by 2035, according to the Canadian Association of Petroleum Producers (CAPP).

Cenovus Energy, one of the most innovative companies operating in Alberta’s oil sands, plans to shell out more than $200 million on research and development this year. Some of that investment will go to the oil producer’s Narrows Lake development to demonstrate its solvent aided process (SAP) now that the project has received regulatory go-ahead from the Alberta Energy Resources Conservation Board. By 2017, Cenovus expects Narrows Lake to produce up to 130,000 barrels per day.

“We have to develop enhanced technologies to ensure we’re progressively improving our environmental footprint,” says Subohd Gupta, Cenovus’ technology advancement advisor.

The company focuses solely on developing enhanced in-situ extraction because the oil it’s going after – as much as 450 metres underground – is too deep to mine. SAP, an enhancement to commonly used steam assisted gravity drainage (SAGD) extraction, involves co-injecting butane (or another solvent such as condensate) with steam to lower the viscosity of the bitumen for freer flow to the surface. The company expects the process to improve its overall steam-to-oil ratio (SOR), which has environmental benefits, and boost oil production rates by up to 30%.

The plan for the Narrows Lake project is to achieve industry leading SORs as low as 1.6. A lower rating means the operation uses less water and natural gas, which results in lower levels of carbon emissions.

Initially, Cenovus will test the SAP process on 25% of its 150 wells during the first and second phases of the project.

“If the technology works out, we’ll go forward with the third phase of the development as well,” says Gupta.

Narrows Lake, a 50/50 partnership between Cenovus and ConocoPhillips, represents the industry’s first use of SAP with butane on a commercial scale. Testing started in 2009 at the Christina Lake development, where Cenovus examined many factors, including how much butane it would inject, the pressure required to maximize extraction yields and how much steam it could cut from production.

It also examined the number of wells the development would need to maximize yield.

“We actually tested to see if we could use fewer wells, and that proved successful,” says Gupta, who sees environmental benefits as significant because the amount of natural gas burned to create steam is reduced. “If you’re reducing your natural gas use at an in-situ extraction operation, you’re essentially cutting the whole operation’s emissions by 25%.”

Spend now, save later

Compared to SAGD projects, SAP will have higher initial costs – up to 20%. And there will be higher capital costs at Narrows Lake since there’s no existing infrastructure. Surface operations will also be more complex. The equipment required to strip excess butane is expensive, but the company expects to make its money back by liberating another 100,000 barrels of oil that would have otherwise been trapped below.

Groundwork for the initial 45,000 barrels per day began in the fall and full SAP production is expected to start by 2017.  Competitors such as Imperial Oil Ltd., Canadian Natural Resources Ltd., and Laricina Energy Ltd. are also trying to perfect the process, which is one of the reasons, according to Gupta, Cenovus pumps so much money into technology development.

“We’ve got up to 150 technology projects on the go at any given time that are all designed to enhance our operations, and reduce energy use and environmental impact. Innovation is key to progressively getting better and staying ahead.”

But some innovations take time. The solvent process is not new. In fact, the Cenovus’ SAP process is 15 years in the making, with initial testing starting in 2002.

But it’s following a shorter timeline that another great extraction innovation, Gupta observes. “It took 30 years to get SAGD to where it is today.”

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This article appears in the March/April 2013 edition of PLANT West.